This application relates to digital image and video processing.
Various coding processes, such as standards MPEG-2, MPEG-4 Part 2, and H.263 standards, divide a picture into 16×16 non-overlapping blocks called macro blocks and then use a 2 dimensional (2D) order-8 discrete cosine transform (DCT) in digital video compression algorithms used in the coding standards. Such processing can be used to achieve low bit rate communications. Recently, new video coding standards, such as H.264/AVC, AVS and SMPTE 421M etc, have been proposed that use 2D (two dimensions) order-4 or order-8 integer cosine transforms to provide a better compressibility than the video standards based on the 2D order-8 DCT. In those standards, order-4 or order-8 integer transforms are used so as to seek a trade-off between computational efficiency and coding efficiency.
An order-N transform achieves data compression by exploiting the redundancy within N data elements. Generally, an order-2N transform exploits the redundancy within more data elements and so can achieve higher data compression than an order-N transform. Therefore, a system or method for generating an order-2N transform from an order-N transform in video or image coding is highly demanded.